/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#include <vector>

#include "tensorflow/compiler/tf2xla/shape_util.h"
#include "tensorflow/compiler/tf2xla/type_util.h"
#include "tensorflow/compiler/tf2xla/xla_op_kernel.h"
#include "tensorflow/compiler/tf2xla/xla_op_registry.h"
#include "tensorflow/compiler/xla/client/xla_builder.h"
#include "tensorflow/core/framework/kernel_def_builder.h"
#include "tensorflow/core/framework/op_kernel.h"

namespace tensorflow {

namespace {

// This TensorFlow op implements the XLA Outfeed primitive.
class OutfeedEnqueueOp : public XlaOpKernel {
 public:
  explicit OutfeedEnqueueOp(OpKernelConstruction* ctx) : XlaOpKernel(ctx) {
    OP_REQUIRES_OK(ctx, ctx->GetAttr("dtype", &dtype_));
  }

  void Compile(XlaOpKernelContext* ctx) override {
    xla::Shape xla_shape;
    OP_REQUIRES_OK(
        ctx, TensorShapeToXLAShape(dtype_, ctx->InputShape(0), &xla_shape));
    // Outfeed configuration is only needed for embedding outfeed.
    const string outfeed_config;
    xla::Outfeed(ctx->Input(0), xla_shape, outfeed_config);
  }

 private:
  DataType dtype_;

  TF_DISALLOW_COPY_AND_ASSIGN(OutfeedEnqueueOp);
};

REGISTER_XLA_OP(Name("OutfeedEnqueue"), OutfeedEnqueueOp);

// This TensorFlow op implements the XLA Outfeed primitive for tuple types.
class OutfeedEnqueueTupleOp : public XlaOpKernel {
 public:
  explicit OutfeedEnqueueTupleOp(OpKernelConstruction* ctx) : XlaOpKernel(ctx) {
    OP_REQUIRES_OK(ctx, ctx->GetAttr("dtypes", &dtypes_));
  }

  void Compile(XlaOpKernelContext* ctx) override {
    std::vector<xla::XlaOp> handles;
    std::vector<TensorShape> shapes;
    auto inputs = ctx->InputList("inputs", &handles, &shapes);

    std::vector<xla::Shape> xla_shapes;
    for (int i = 0; i < shapes.size(); ++i) {
      xla::Shape xla_shape;
      OP_REQUIRES_OK(ctx,
                     TensorShapeToXLAShape(dtypes_[i], shapes[i], &xla_shape));
      xla_shapes.push_back(xla_shape);
    }
    xla::Shape tuple_shape = xla::ShapeUtil::MakeTupleShape(xla_shapes);
    VLOG(1) << "OutfeedEnqueueTuple: "
            << xla::ShapeUtil::HumanStringWithLayout(tuple_shape);
    auto b = ctx->builder();
    auto tuple = xla::Tuple(b, handles);
    // Outfeed configuration is only needed for embedding outfeed.
    const string outfeed_config;
    xla::Outfeed(tuple, tuple_shape, outfeed_config);
  }

 private:
  DataTypeVector dtypes_;

  TF_DISALLOW_COPY_AND_ASSIGN(OutfeedEnqueueTupleOp);
};

REGISTER_XLA_OP(Name("OutfeedEnqueueTuple"), OutfeedEnqueueTupleOp);

}  // anonymous namespace
}  // namespace tensorflow
